Investigating Use of a Parent Report Tool to Measure Vocabulary Development in Deaf Greek-speaking Children with Cochlear Implants

Objective: There are very few measures of language development in spoken Greek that can be used with young deaf children. This study investigated the use of Cyprus Lexical List (CYLEX), a receptive and expressive vocabulary assessment based on parent report that has recently been adapted to Standard Greek, to measure the vocabulary development of deaf Greek-speaking children with cochlear implants. Design: A Standard Greek version of CYLEX was used to collect data on receptive and expressive vocabulary development from parents of thirteen deaf children with cochlear implants aged between 21 and 71 months. These data were compared with data collected previously from typically developing hearing Greek-speaking children. Results: Use of the test by parents of deaf children was found to be reliable. No correlation was found between children's vocabulary scores and chronological age. A positive correlation was however found between children's post-implant age and expressive vocabulary. The vocabulary skills of implanted children with a mean post-implant age of 20 months were not significantly different from those of typically developing hearing children of similar chronological age. Conclusion: CYLEX is a reliable and useful tool for exploring vocabulary development with this clinical group. Findings confirm the results of other studies in indicating that the vocabulary size of implanted pre-school-aged deaf children is related to the amount of time that children have used their implant, rather than chronological age

V-I characteristics in the vicinity of order-disorder transition in vortex matter

The shape of the V-I characteristics leading to a peak in the differential resistance r_d=dV/dI in the vicinity of the order-disorder transition in NbSe2 is investigated. r_d is large when measured by dc current. However, for a small Iac on a dc bias r_d decreases rapidly with frequency, even at a few Hz, and displays a large out-of-phase signal. In contrast, the ac response increases with frequency in the absence of dc bias. These surprisingly opposite phenomena and the peak in r_d are shown to result from a dynamic coexistence of two vortex matter phases rather than from the commonly assumed plastic depinning.Comment: 12 pages 4 figures. Accepted for publication in PRB rapi

Dynamic ordering and frustration of confined vortex rows studied by mode-locking experiments

The flow properties of confined vortex matter driven through disordered mesoscopic channels are investigated by mode locking (ML) experiments. The observed ML effects allow to trace the evolution of both the structure and the number of confined rows and their match to the channel width as function of magnetic field. From a detailed analysis of the ML behavior for the case of 3-rows we obtain ({\it i}) the pinning frequency $f_p$, ({\it ii}) the onset frequency $f_c$ for ML ($\propto$ ordering velocity) and ({\it iii}) the fraction $L_{ML}/L$ of coherently moving 3-row regions in the channel. The field dependence of these quantities shows that, at matching, where $L_{ML}$ is maximum, the pinning strength is small and the ordering velocity is low, while at mismatch, where $L_{ML}$ is small, both the pinning force and the ordering velocity are enhanced. Further, we find that $f_c \propto f_p^2$, consistent with the dynamic ordering theory of Koshelev and Vinokur. The microscopic nature of the flow and the ordering phenomena will also be discussed.Comment: 10 pages, 7 figure, submitted to PRB. Discussion has been improved and a figure has been adde

Multiscale formulation for material failure accounting for cohesive cracks at the macro and micro scales

This contribution presents a two-scale formulation devised to simulate failure in materials with het- erogeneous micro-structure. The mechanical model accounts for the activation of cohesive cracks in the micro-scale domain. The evolution/propagation of cohesive micro-cracks can induce material instability at the macro-scale level. Then, a cohesive crack is activated in the macro-scale model which considers, in a homogenized sense, the constitutive response of the intricate failure mode taking place in the smaller length scale.The two-scale model is based on the concept of Representative Volume Element (RVE). It is designed following an axiomatic variational structure. Two hypotheses are introduced in order to build the foundations of the entire two-scale theory, namely: (i) a mechanism for transferring kinematical information from macro- to-micro scale along with the concept of “Kinematical Admissibility”, relating both primal descriptions, and (ii) a Multiscale Variational Principle of internal virtual power equivalence between the involved scales of analysis. The homogenization formulae for the generalized stresses, as well as the equilibrium equations at the micro-scale, are consequences of the variational statement of the problem.The present multiscale technique is a generalization of a previous model proposed by the authors and could be viewed as an application of a general framework recently proposed by the authors. The main novelty in this article lies on the fact that failure modes in the micro-structure now involve a set of multiple cohesive cracks, connected or disconnected, with arbitrary orientation, conforming a complex tortuous failure path. Tortuosity is a topic of decisive importance in the modelling of material degradation due to crack propagation. Following the present multiscale modelling approach, the tortuosity effect is introduced in order to satisfy the “Kinematical Admissibility” concept, when the macro-scale kinematics is transferred into the micro-scale domain. There- fore, it has a direct consequence in the homogenized mechanical response, in the sense that the proposed scale transition method (including the tortuosity effect) retrieves the correct post-critical response.Coupled (macro-micro) numerical examples are presented showing the potentialities of the model to sim- ulate complex and realistic fracture problems in heterogeneous materials. In order to validate the multiscale technique in a rigorous manner, comparisons with the so-called DNS (Direct Numerical Solution) approach are also presented

Major findings of the LOCHI study on children at 3 years of age and implications for audiological management

Objective: This article describes the major findings of the Longitudinal Outcomes of Children with Hearing Impairment (LOCHI) study. Design: A population-based prospective cohort study; with randomized controlled trials of hearing aid prescription and non-linear frequency compression. Sample: 451 children in New South Wales, Victoria and Southern Queensland. Results: Significant predictors of language outcomes at 3 years of age included severity of hearing loss, gender, presence of additional disabilities, maternal education, and age at cochlear implantation. Although prescription did not have a significant effect on outcomes, its influence on loudness and hearing aid safety has implications for management. After controlling for a range of predictor variables, nonlinear frequency compression did not have a significant effect on outcomes. For the same hearing sensitivity, the presence of auditory neuropathy did not have a significant effect on outcomes. Conclusions: These findings form the basis for evidence-based guidelines for management of children with hearing loss.4 page(s

Audiovisual tools for phonetic and articulatory visu­alitation in computer-aided pronunciation training

Abstract. This paper reviews interactive methods for improving the phonetic competence of subjects in the case of second language learning as well as in the case of speech therapy for subjects suffering from hearing-impairments or articulation disorders. As an example our audiovisual feedback software “Speech-Trainer ” for improving the pronunciation quality of Standard German by visually highlighting acoustics-related and articulation-related sound features will be introduced here. Results from literature on training methods as well as the results concerning our own software indicate that audiovisual tools for phonetic and articulatory visualization are beneficial for computer-aided pronunciation training environments